Culture and religion cannot be used as an excuse for discriminating against women, Cherie Blair has argued.
The human rights lawyer, wife of former PM Tony Blair, said all the major world faiths shared "an insistence on the dignity of all God's people".
In a speech, she said discrimination on religious grounds was a "distortion" of the true message of some faiths.
Mrs Blair, a Catholic, also said she could not claim British society was perfect, citing the gender pay gap.
In a lecture on Wednesday, organised by the BBC's Today programme and Chatham House, she pointed out new laws in Egypt which gave men and women different rights on divorce.
She also highlighted Orthodox Jewish practices under which a woman cannot divorce without her husband's consent.
And, in many areas, she said, "proclaimed adherence to a specific religion or system of belief or culture is intimately tied to women's continuing discrimation and abuse".
She rejected the view that human rights could not be exported to some countries because of religious or cultural differences saying "human rights are universal".
And she rejected the notion that Islam was innately discriminatory towards women by suggesting that the use of Sharia law in some Muslim countries went against the true precepts of the faith.
"It is not laid down in the Koran that women can be beaten by their husbands or that their evidence should be devalued, as it is in some Islamic courts," she said.
"It is important for judges and political leaders to remind everyone that the philosophical purpose of the Sharia is to protect and promote human welfare."
Earlier Mrs Blair told the BBC, religion was "subject to interpretation" by "fallible human beings, mainly men" who were not necessarily true to the principle of equal rights.
But she refused to support the Lib Dems' boycott of the visit of Saudi King Abdullah, saying it was important to engage in dialogue and exchange views to "find cultural change".
On Islamic veils she pointed out she had been brought up by Catholic nuns who wore veils and had no problem with women covering their heads.
But on full-face veils she added: "I think however, that if you get to the stage where a woman is not able to express her personality because we cannot see her face, then we do have to ask whether this is something that is actually acknowledging the woman's right to be a person."
But she added: "I think we have to be careful about judging people by their appearances."